The invention relates to a device for cutting of bags of paper, synthetic material, jutes or the like containing powdery up to granular and/or granulated or flocculent materials, as well as for loosening or separation of the goods from the bag or its parts, consisting of a receiving housing supplied by the conveyer, and including a cutting mechanism, a sieve drum disposed in the housing having respective separate outlets for the bag parts, for the goods to be discharged, as well as for any oversized particles to be separated.
From DE-AS No. 1,209,951 there has become known a bag-tearing apart discharge mechanism, in which the filled bag is fragmented and supplied to a sieve arrangement through a chute, by means of which the separation and sifting of the bag contents from the bag material is accomplished.
In this mechanism there are disposed in a so-called "cutter roller housing" two cutting rollers located next to one another, and in parallel, driven at respective opposite directions, and provided on the periphery with radially disposed cutters in such a manner that the cutters cam with one another.
As mesh mechanism there is provided a sieve drum which is disposed substantially horizontally in the direction of the outlet, and which is conically diverging, so as to attain good conveyance conditions within the drum, without there being provided any particular formation of the drum units, such good conveyance conditions being otherwise available only in the case of an inclined drum.
The cut bags are supplied through a widened region into a delivery chute, while the sieve is received below the screw conveyor by a collecting worm gear, and is withdrawn from the collecting worm gear, for example by means of a pneumatic supply arrangement.
It is a disadvantage of this arrangement, that the introduction of the bags between the oppositely driven cutter rollers is accomplished practically without any precoupled separate alignment arrangement, so that the bag is introduced between the cutter rollers without necessarily always being optimally aligned. The cutter rollers, which provide for a plurality of cutters arranged in star configurations separated by gaps therebetween, fragment the bags into pieces of uncontrollable size which have predominantly cut edges.
In this connection, it is to be pointed out that it is just the cut rim regions of bag parts, which, due to accumulation and adhesion of powdery goods impair conveyance, so that the separation of the remaining goods from the bag material is made much more difficult.
Further disadvantages of this arrangement are, amongst others, the increased tendency for a rapid passage of a substantial portion of the powdery-to-granulate material up to the end region of the drum due to the conical widening, so that a receiving device disposed therebelow, in this case a screw conveyor, is loaded in its end region considerably more than in its inlet region.
This can lead to accumulations, and also to overflow or the material in the direction of bag wastages.
A particular problem exists for all cutting mechanisms, which are required to have cutters cutting into the bag at approximately the same depth from above and from below, if the bag is damaged, during the transport to the device, through any external influences, so that the volume, particularly the thickness of the bag, is reduced, and so that a so-called "limp bag" is obtained.
In such a case it is possible that only the receiving surface of the bag on the inlet floor is cut, while the bag portion disposed thereabove is passed practically without any separation approximately at the size of the support surface of the bag, into the sieve drum, which can cause accumulations and disturbances there.